Morphological and physiological behaviour of sea barley (Hordeum marinum ssp marinum) genotypes originating from Soliman Sebkha under increasing salinity

Abstract

Evaluation of germplasm in salt stress environment may help identifying salt-tolerant genotypes. In this study, we analyzed the genetic diversity of Hordeum marinum, genotypes originated from Soliman Sebkha in response to salinity (0, 250 and 400 mM) by measuring a set of parameters related to growth, water statue and photosynthetic activity. Results of ANOVA showed that variability of measured parameters was explained by the effects genotypes, treatment and their interaction, with treatment factor recorded the highest values. Salinity significantly reduced the photosynthetic rate and related parameters, including stomatal conductance (gs), intercellular CO2 concentration (Ci), and transpiration (E). Several indices for salt tolerance indices comprising tolerance index (TOL), stress tolerance index (STI) and Salt Tolerance (ST) were calculated based on drought biomass (ADW) under non-stressed and under stress conditions. Results showed that lower values of TOL and higher values of ST and STI indicate the superiority of the genotypes having enough plasticity to respond to extreme conditions. Principal Component Analysis clustered genotypes into sensitive (21.43%), moderately tolerant (50%), and highly tolerant (28.57%) groups, depending on their relative potential to sustain good growth under high salinity. Results indicating sufficient genetic variability for salinity tolerance among the studied genotypes, hence tolerant genotypes can be good candidates in future breeding programs.

Keywords

• Hordeum marinum
• photosynthesis activity
• salt tolerance indices
• salinity stress